A dual-channel supply chain model is considered, in which the retailer is capital constrained. In the case of symmetric demand information, according to the different ways for disposing the capital insufficient problem, by using the Stackelberg game theory, the deferred-payment model and the loan-payment model are analyzed respectively, and the optimal decisions of the supplier and retailer are given under the two modes. It is proved that not only the retailer’s profit can be increased, but also it is conducive to expanding the demand for retailing channel and raising the retailer’s competitiveness in market, when the retailer chooses to defer its payment for bill. It is showed that no matter how much the producing-budget owns, the supplier is always willing to provide the retailer a deferred-payment policy. Finally, a numerical example is given to illustrate the correctness of the conclusions.